In networking systems, a single server may be utilized to concurrently support multiple server operations or services. For example, a single server may be utilized for providing access to business applications while also operating as an email server, a database server, and/or an exchange server. The server may generally support the various server operations by utilizing a single operating system (OS). The server operations, via the single OS, make use of server processing resources such as the central processing unit (CPU), memory, network interface card (NIC), peripheral sound card, and/or graphics card, for example. In many instances, the server resources may not be efficiently utilized because the demand for server operations generally vary based on the type of service provided and/or user needs. Consolidating server services into a single operation may result in an improvement in server efficiency. However, consolidation also removes the level of protection that is provided when the operations are maintained separate. For example, when the operations are consolidated, a crash or failure in a database server may also result in the loss of email services, exchange services, and/or application services.
Another approach for improving server efficiency may be to utilize multiple operating systems running concurrently to so that each operating system supports a different server operation, for example. The multiple operation systems may be referred to as guest operating systems (GOSs). This approach maintains the level of protection provided when server operations are not consolidated while also enabling the optimization of the usage of the processing resources available to the server. The use of multiple guest operating systems may be referred to as OS virtualization because each GOS perceives to have full access to the server's hardware resources. In this regard, a GOS is unaware of the presence of any other GOS running on the server. In order to implement OS virtualization, a software layer may be needed to arbitrate access to the server's hardware resources. This software layer may be referred to as a hypervisor or virtual machine (VM) monitor, for example. The hypervisor may enable the multiple GOSs to access the hardware resources in a time-sharing manner.
A hardware resource that may be frequently utilized by at least one of the server operations or services is the NIC. In this regard, a hypervisor or VM monitor may enable creating a software representation of NIC that may be utilized by a GOS. This software representation of the NIC may be referred to as a “virtual NIC.” However, a virtual NIC may be limited as to the kind of features or functionalities of the NIC that may be provided to the GOSs. For example, a virtual NIC may not be able to support transmission control protocol (TCP) offload functions. Offloading at least part of the TCP processing from the CPU to a processor on the NIC may provide improved network throughput. Without offloading capabilities, the data rate of the server may be limited in some circumstances. Another limiting aspect may be that a virtual NIC may only provide basic layer 2 (L2) networking functionality to the multiple GOSs. The virtual NIC may be limited to providing data communication between the GOSs and the network. In this regard, the virtual NIC may not be able to support other advanced features such as remote direct memory access (RDMA) and/or Internet small computers system interface (iSCSI), for example.
In addition to the limitations on the kind of features that may be provided by the virtual NIC, the hypervisor may also be required to do a significant amount of work when managing the interaction between the multiple GOSs and the server's hardware resources. Utilizing a hypervisor layer may introduce an overhead penalty to basic L2 networking operations that may not be present when a single OS is utilized. For example, when data is to be transmitted from any of the GOSs, the hypervisor may be required to arbitrate access to the NIC. When data is received by the NIC, the hypervisor may be required to determine which one is the appropriate GOS to send the received data. Moreover, because each GOS and the hypervisor may utilize different portions of memory, the hypervisor may have the added responsibility of managing the transfer of data from one portion of memory to another.
Due to the growing demand to support multiple GOSs in a single server, new solutions may require that the overhead introduced by the presence of a hypervisor layer be reduced and/or that advance features may be supported by the virtualization of a portion of the server's hardware resources such as the network interface card.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.